Question

A body, starting from rest, attains a linear momentum of 125 kg-m/sec under the action of 250 N force. How long does the force acts on the body?

Answer 1

Answer :

• Time taken for the force 250 N to act on the body with linear momentum 125 kg m/s is , ∆t = 0.5 s

Explanation :

Given :

• Linear momentum of the body , ∆p = 125 kg m/s.

• Force acting on the body , F = 250 N.

To find :

• Time taken for the force 250 N to act on the body with linear momentum 125 kg m/s is , ∆t = ?

Knowledge required :

We know that rate of change of linear momentum is equal to the product of mass and acceleration of the body.

So,

Mathematically,

⠀⠀⠀⠀⠀⠀⠀⠀⠀ma = ∆p/∆t

But we know that the product of mass and acceleration is the force applied on the body , i.e,

⠀⠀⠀⠀⠀⠀⠀⠀⠀F = ma

So by using it in the relation of change of linear momentum , we get :

⠀⠀⠀⠀⠀⠀⠀⠀⠀F = ∆p/∆t

Solution :

By using the relation between force and change of linear momentum and substituting the values in it, we get :

==> F = ∆p/∆t

==> F/∆p = 1/∆t

==> ∆t = ∆p/F

==> ∆t = 125/250

==> ∆t = 0.5

∴ ∆t = 0.5 s

Therefore,

• For 0.5 s the force of 250 N acts on the body with linear momentum 125 kg m/s.

Answer 2

Explanation:

Given :

• A body, starting from rest, attains a linear momentum of 125 kg-m/sec under

• the action of 250 N force.

To Find :

• How long does the force acts on the body?

Solution :

F = p / t

Putting all Value :

250 = 125 / t

t = 125 / 250

t = 0.5 second

0.5 sec does the force acts on the body